不同浓度四君子汤对尾部悬吊大鼠比目鱼肌肌萎缩的影响

目的 观察不同浓度四君子汤对尾部悬吊大鼠比目鱼肌肌萎缩的影响.方法 尾部悬吊法建立模拟失重模型,30只Sprague-Dawley大鼠随机分为5组,同步饲养组(CON)、尾吊组(HLU-W)、尾吊+四君子汤高(HLU-H)、中(HLU-M)、低(HLU-L)浓度组,每组6只.用免疫组织化学法观察药物对比目鱼肌肌球蛋白重链(MHC)的影响.结果 与尾吊组相比,四君子汤高、中浓度组使比目鱼肌湿重分别增加了33.11%和37.57%,与同步饲养组亦无显著性差异;四君子汤高、中、低浓度组使比目鱼肌I型肌纤维比例增加了34.04%～54.90%,I型肌横截面积增加了8.50%～36.86%,且中浓度组与同步饲养组相比亦无显著性差异.结论 3种浓度的四君子汤对模拟失重引起的比目鱼肌肌萎缩有显著的对抗作用,且中浓度四君子汤的效果优于高、低浓度.     

尾部悬吊与30月龄大鼠比目鱼肌的形态学特征比较

目的 观察尾部悬吊和30月龄大鼠比目鱼肌发生萎缩过程的异同点.方法 SD雄性大鼠42只,随机分为7组,即尾部悬吊5 d、7 d、14 d组,相应的同步对照和30月鼠龄组,在各时间点制备比目鱼肌横截面冰冻切片标本,用抗MHC Ⅱ单克隆抗体进行免疫组织化学染色,计算比目鱼肌Ⅰ、Ⅱ型肌纤维横截面积并计数各型肌纤维数目.结果 与同步对照组相比,悬吊组大鼠比目鱼肌的湿重,相对湿重,Ⅰ、Ⅱ型肌纤维横截面积,经体重归一化的肌纤维横截面积均显著降低,Ⅱ型肌纤维比例显著增加,而Ⅰ型肌纤维比例减少.与14 d对照组相比,30月龄组大鼠比目鱼肌湿重和Ⅰ、Ⅱ型肌纤维横截面积均明显增大,但其相对湿重和经体重归一化的肌纤维横截面积却显著降低,与悬吊14 d组无显著差异.30月龄组大鼠比目鱼肌中Ⅰ、Ⅱ型肌纤维比例与各对照组相比亦无显著差异.结论 30月龄大鼠比目鱼肌萎缩以首先出现相对湿重与归一化肌纤维横截面积降低为特征,且发生较慢,而尾部悬吊大鼠比目鱼肌则在较短时间内发生全面萎缩.     

多穴位电针刺激对抗模拟失重大鼠比目鱼肌萎缩作用研究

目的研究电针刺激对抗模拟失重大鼠比目鱼肌萎缩的作用。方法采用-30°尾吊大鼠模型模拟失重的生理效应。雄性Wistar大鼠随机分成3组,每组10只(n=10):对照组(CON)、30 d尾吊组(TS)和30 d尾吊+多穴位刺激组(TS+MA)。CON组自由活动;TS组大鼠尾吊30 d;TS+MA组大鼠尾吊30 d,外加韩氏穴位神经刺激仪双侧对称穴位隔日刺激30 min。结果 TS组大鼠比目鱼肌肌纤维束排列不规则,肌纤维横截面积变小,间质水肿并有大量炎性细胞浸润;TS+MA组与TS组变化相似,但肌细胞核数量增多,没有观察到炎性细胞浸润。与CON组比,TS和TS+MA组大鼠Ⅱ型肌纤维数量均出现显著增加(P0.01);与TS组比,TS+MA组肌纤维数量显著下降(P0.01)。与CON组比,TS组大鼠比目鱼肌指数显著降低(P0.05),TS+MA组无显著差异。结论多穴位电针刺激对抗模拟失重所导致的大鼠比目鱼肌萎缩作用明显,但更好的穴位刺激处方和刺激方式有待进一步探索。     

4 h/d站立可防止4周尾部悬吊大鼠比目鱼肌的萎缩

目的依据比目鱼肌湿重、不同型肌纤维横截面积及比例与聚丙烯酰胺凝胶电泳分离肌球蛋白重链(mvosin heavy chain,MHC)异构体比例的变化,评价4h／d站立是否可防止模拟失重下比目鱼肌的萎缩。方法雄性SD大鼠18只,按体重配对原则随机分为3组,每组6只：即对照组(CON),尾部悬吊4周组(TS)及尾部悬吊 4h／d站立组(TS STD4)。4周后,取双侧肾上腺及比目鱼肌(soleus,SOL),称取湿重。左侧SOL行冰冻切片,ATP酶钙钴法染色以观察骨骼肌肌纤维种类及横截面积。右侧SOL行组织匀浆,在70V、40C下,于8％凝胶上电泳28h,考马斯亮蓝染色,用Scion image软件对MHC条带进行光密度容积的测量,得出不同MHC异构体的比例。结果4周模拟失重导致双侧后肢骨骼肌SOL的湿重、Ⅰ型与Ⅱ型肌纤维横截面积、Ⅰ型肌纤维比例及MHCI的比例均显著降低(P＜0、01或P＜0．05)。4h／d间断性站立可完全防止比目鱼肌上述指标的变化,与CON组相比无显著差异(P＞0．05)。结论每日4h站立可完全防止模拟失重大鼠SOL萎缩。     

Na2ATP对尾部悬吊大鼠比目鱼肌梭内、外肌纤维MHC表达的影响

目的 探讨三磷酸腺苷二钠盐（Na2ATP）对尾部悬吊大鼠比目鱼肌（SOL）梭内、外肌纤维肌球蛋白重链（MHC）表达的影响。方法 采用大鼠尾部悬吊法建立废用模型，用免疫组织化学技术，观察Na2ATP注射液对大鼠比目鱼肌（SOL）梭内、外肌纤维MHC表达的影响。结果 尾部悬吊14d后大鼠比目鱼肌梭内、外肌纤维中快缩型MHC的表达均有所增加，而在尾吊期间注射Na2ATP后比目鱼肌梭内、外肌快缩型MHC表达没有明显变化。结论 Na2ATP注射液对尾部悬吊大鼠比目鱼肌梭内、外肌纤维MHC表型转化有明显的对抗作用。     

氯化胆碱对尾吊大鼠比目鱼肌肌萎缩对抗效果的观察

目的 探讨氯化胆碱对尾吊大鼠比目鱼肌肌萎缩的影响。方法 按体重配对原则将24只雌性SD大鼠分为对照组（CON）、尾吊组（TS）与尾吊给药组（TS＋Cch），每组8只。尾部悬吊法建立模拟失重模型，1／2尾吊大鼠按150mg／kg的剂量用氯化胆碱灌胃，连续14d。Ca^2＋-ATPase法测定比目鱼肌（SOL）的mATPase活性，常规方法制作石蜡组织切片。结果 1）以氯化胆碱灌胃后，尾吊大鼠SOL中Ⅰ型肌纤维比例明显升高，Ⅱ型肌纤维比例明显降低，P〈0．001；2）以氯化胆碱灌胃后，尾吊大鼠SOL的肌束之间间隙减小，Ⅰ型肌纤维横截面积（CSA）明显升高，P〈0．001，Ⅱ型肌纤维CSA和单根肌纤维的平均CSA亦明显高于尾吊组，P〈0．05；3）以氯化胆碱灌胃后，尾吊大鼠SOL的梭内肌纤维中，一核链纤维的mATPase染色呈阴性，其它各纤维与尾吊组相同，均呈阳性。结论氯化胆碱对模拟失重条件下大鼠SOL慢肌向快肌的转化与模拟失重引起的肌萎缩均有显著的对抗作用。     

川芎嗪和黄芪对尾部悬吊大鼠比目鱼肌肌球蛋白ATP酶活性及肌萎缩的影响

目的 探讨川芎嗪和黄芪对吊尾大鼠比目鱼肌（SOL）肌球蛋白ATP酶（mATPase）活性及肌萎缩的影响。方法 尾部悬吊法建立模拟失重模型,Ca^2＋-ATPase法测定SOL的mATPase活性。结果 1）与吊尾组（TS）相比,在腹腔注射川芎嗪组和黄芪组,SOL中Ⅱ型肌纤维比例均显著降低,且黄芪组Ⅰ、Ⅱ型肌纤维的比例与同步饲养组相比亦无显著差异;2）川芎嗪组SOL中Ⅰ型肌纤维横截面积（CSA）显著增大,与同步饲养组相比无显著性差异,黄芪组Ⅰ、Ⅱ型肌纤维CSA及平均CSA均显著地增大,且与同步饲养组相比亦无显著性差异;3）川芎嗪组和黄芪组梭内肌各纤维的mATPase染色均与同步饲养组相近。结论 川芎嗪和黄芪对大鼠SOL的失重性肌萎缩及慢肌向快肌的转化均有明显的对抗作用,且均可显著抑制模拟失重导致的梭内肌各纤维mATPase活性的升高。     

高频振动对尾部悬吊大鼠比目鱼肌梭内、外肌纤维肌球蛋白重链表达的影响

目的 观察高频正统波振动对尾部悬吊大鼠比目鱼肌（SOL）梭内、外肌纤维MHC表达的影响。方法 采用大鼠尾部悬吊法建立模拟失重模型,高频正弦波振动大鼠比目鱼肌。用免疫组织化学技术,观察大鼠比目鱼肌（SOL）梭内、外肌纤维MHC表达变化。结果 尾部悬吊7d后大鼠比目鱼肌梭内、外肌纤维中快缩型MHC的表达均有所增加,而在另尾期间给予高频正弦波振动比目鱼肌后梭内、外肌快缩型MHC表达没有明显变化。结论 高频正弦波振动尾部悬吊大鼠比目鱼肌梭内、外肌纤维MHC表型转化有明显的对抗作用。     

模拟失重对大鼠比目鱼肌梭内肌纤维肌球蛋白重链表达的影响

目的 检查模拟失重对大鼠比目鱼肌梭内肌纤维肌球蛋白重链表达的影响，探讨模拟失重所致肌梭退变的机制。方法 采用免疫过氧化酶反应ABC法观察尾悬吊7d，14d与对照组大鼠比目鱼肌梭内肌纤维对特异性抗小鸡肌球蛋白重链慢紧张型(ALD58)和快缩型(MF30)单克隆抗体表达的差别。结果 梭外肌纤维不与ALD58和MF30起反应。这两种抗体仅与梭内肌纤维反应。核袋1和核袋2纤维对ALD58抗体起反应。核袋2和核链纤维对MF30抗体起反应。尾悬吊7d后，核袋1和核袋2纤维对ALD58的免疫反应性降低，而核袋2和核链纤维对MF30免疫反应性增强。尾悬吊14d后，核袋1和核袋2纤维对ALD58的免疫反应性明显降低，甚至消失。而所有的梭内肌纤维对MF30都起免疫反应，并且明显增强。结论 模拟失重可致大鼠比目鱼肌梭内肌纤维肌球蛋白重链的表达水平和表型发生改变。     

基于实时剪切波弹性成像评价毛蕊异黄酮预防失重性肌萎缩的效果

目的采用实时剪切波弹性成像(real-time shear wave elastography, RT-SWE)探究毛蕊异黄酮抗失重性肌萎缩的防护效果。方法通过系统药理学方法筛选出黄芪中抗肌萎缩的潜在关键活性化合物毛蕊异黄酮。18只健康雄性Sprague-Dawley大鼠按随机数字表法分为对照组[0.5%羧甲基纤维素钠(carboxymethyl cellulose-Na, CMC-Na)灌胃]、尾悬吊(hind limb unloading, HLU)+CMC-Na组(HLU+0.5%CMC-Na灌胃)和HLU+毛蕊异黄酮组(HLU+毛蕊异黄酮灌胃), 每组6只。连续灌胃28 d后, 分别检测大鼠脏器指数、肝肾毒性、比目鱼肌组织湿重及肌重体重比。采用非侵入式的RT-SWE评价各组大鼠股直肌的厚度和弹性模量;组间差异比较采用单因素方差分析。结果不同组间大鼠脏器指数和肝肾毒性差异无统计学意义(P均>0.05)。不同组间大鼠比目鱼肌重量及肌重体重比差异有统计学意义(F=60.66、56.44, P均<0.001);与HLU+CMC-Na组相比, HLU+毛蕊异黄酮组大鼠的比目鱼...     

Muscle composition after 14-day hindlimb unloading in rats: effects of two herbal compounds

AIM: We studied the potential of two herbal compounds (HC-1 and HC-2) in different dosages (HC-1, containing ligustrazine; HC-2, containing radix astragali) as a countermeasure against muscle atrophy in a hindlimb unloading rat model. Soleus muscle weight, fiber type distribution, cross-sectional area (CSA), and myosin ATPase activity were measured. METHODS: Six rats each were assigned to a nine-group design: Control (CON); hindlimb unloading only (HLU); hindlimb unloading plus intragastric water instillation (HLU-W); and hindlimb unloading plus different dosages of instilled HC-1 (HLU-HC-1l, HLU-HC-1m, HLU-HC-1h) or HC-2 (HLU-HC-2l, HLU-HC-2m, HLU-HC-2h). RESULTS: As expected, in HLU and HLU-W, soleus muscle-to-body weight ratio and CSA of type I and II fiber went down, and myosin ATPase activity and the percentage of type II fibers went up, all compared with CON. Compared to untreated rats, high-dose HC-1 enhanced type I and II fiber CSA by 77% and 55%, respectively; myosin ATPase activity (type II fiber percentage) were lower, but soleus muscle-to-body weight ratio did not change. High-dose HC-2 enhanced soleus muscle-to-body weight ratio by 33%; and type I / type II fiber CSA by 143% and 83% above HLU-W values, respectively, and resulted in a slower myosin ATPase activity (corresponding to a lower type II fiber percentage). Low- to mid-dose HC-1 and HC-2 showed some preventive effects as well. CONCLUSION: HC-1 and HC-2 in proper dosages diminished muscle atrophy that otherwise occurs in simulated weightlessness.     

去负荷肌萎缩对小鼠后肢骨骼肌收缩特性的影响

目的探讨去负荷引起的小鼠后肢肌肉萎缩后,骨骼肌收缩能力和疲劳度特性的变化。方法小鼠后肢去负荷14 d、28 d引起骨骼肌萎缩后,采用离体肌肉灌流技术,给予慢肌比目鱼肌和快肌跖肌一定模式的电刺激,观察慢肌和快肌单收缩、强直收缩能力和肌疲劳度等收缩特性的改变。结果 1)去负荷14 d时小鼠后肢比目鱼肌质量明显下降(P<0.01),肌肉萎缩至高峰,之后萎缩减慢,但是快肌萎缩出现地相对较晚;2)离体灌流肌肉的单收缩力和强直收缩力检测表明,比目鱼肌单收缩力和强直收缩力进行性下降,在去负荷后14 d时即有明显差异(P<0.05),而对于快肌跖肌,单收缩力和强直收缩力并没有出现显著性差异的改变;3)离体灌流肌肉的肌疲劳度检测发现,虽然后肢快慢肌疲劳程度呈下降趋势,但仅在去负荷28 d时才观察到比目鱼肌的显著性改变(P<0.05)。结论去负荷肌萎缩后,小鼠后肢骨骼肌快肌和慢肌的单收缩力、强直收缩收缩力进行性降低,且慢肌尤为显著;而肌疲劳度的下降则选择性地在慢肌比目鱼肌中发生。     

Fiber size,type, and myosin heavy chain content in rhesus hindlimb muscles after 2 weeks at 2 G

BACKGROUND: Fiber atrophy and an increase in the percentage of fast fibers have been observed in Rhesus leg muscles after spaceflight. Hypothesis: Hypergravity will result in muscle fiber hypertrophy and an increase in the percentage of slow fibers. METHODS: Open muscle biopsies were obtained from Rhesus soleus, medial gastrocnemius (MG), and tibialis anterior (TA) muscles before and after 14 d of centrifugation (2 G) and in time-matched controls. Cage activity levels were measured by telemetry. RESULTS: Based on monoclonal antibody binding for myosin heavy chains (MHC), the fastest region of soleus contained a higher proportion of type I+II (27 vs. 13%) and had a tendency for a lower proportion of type I (38 vs. 61%, p = 0.10) fibers after than before centrifugation. There was a higher proportion of type I+II fibers in post- vs. pre-2 G (10 vs. 0.6%) MG biopsies. Fiber type distribution and MHC composition were unaffected in the TA. Overall, mean fiber sizes were unaffected by centrifugation. Average cage activity levels were 36% lower during than before 2 G. CONCLUSIONS: Our hypothesis was rejected. The changes in the proportion of fibers expressing type I MHC are the reverse of that expected with chronic loading of extensors and, paradoxically, are similar to changes observed with chronic unloading, such as occurs during spaceflight, in this primate model. The data are consistent with the observed decrease in total daily activity levels.     

硝苯地平对去负荷比目鱼肌肌球蛋白重链(MHC)异构体转化的影响

目的观测L型钙离子通道抑制剂硝苯地平对尾部悬吊大鼠比目鱼肌重量,以及肌球蛋白重链(MHC)表达水平的影响。方法经饮水每天给予大鼠10mg／kg体重的硝苯地平1与2周。称量比目鱼肌(SOL)与趾长伸肌(EDL)的湿重,用低温SDS-聚丙烯酰胺凝胶电泳观测MHC异构体蛋白表达,并用RT—PCR方法观测MHCmRNA的表达。结果与正常对照组相比,给予硝苯地平处理1与2周的同步对照组大鼠SOL的相对重量未见明显改变;而尾部悬吊1周与2周大鼠SOL的相对重量则分别降低了39．5％和51．7％。经硝苯地平处理的1与2周悬吊大鼠的SOL相对重量较其对照组分别降低了36．6％与52．0％,但与同步悬吊组相比,无明显差异。各组EDL相对重量均未见明显改变。正常对照组与经硝苯地平处理的对照组可检测到MHCⅠ、Ⅱa mRNA与蛋白的表达,悬吊组与经硝苯地平处理的悬吊组可检测到MHCⅠ、Ⅱa、Ⅱb与Ⅱx mRNA以及MHCⅠ与Ⅱa蛋白的表达。在对照组与悬吊组,硝苯地平对Ⅱ型MHC mRNA表达均产生抑制作用,并降低MHC Ⅱa蛋白表达。结论硝苯地平不能防止去负荷引起的SOL萎缩,但在转录水平抑制萎缩SOL的MHC异构体由慢型向快型转化。     

Functional adaptability of muscle fibers to long-term resistance exercise

PURPOSE: We compared the functional properties of muscle fibers from two groups of subjects that differed widely in their training history to investigate whether long-term resistance exercise alters the intrinsic contractile properties of skeletal muscle fibers. METHODS: Vastus lateralis muscle biopsies were obtained from six sedentary males (NT group, age = 23 +/- 1 yr) and six males who had participated in regular resistance exercise training over the preceding 7.6 +/- 1.6 yr (RT group, 22 +/- 1 yr). Chemically skinned muscle fiber segments were activated with a saturating free [Ca2+] to quantify fiber peak Ca2+-activated force (P(o)), unloaded shortening velocity (V(o)), and peak power. Fiber segment myosin heavy chain (MHC) isoform content was identified by gel electrophoresis. RESULTS: Slow and fast fibers from the RT group were larger in CSA and produced greater absolute P(o) and absolute peak power in comparison with fibers from the NT group. However, these differences were no longer evident after P(o) and peak power were normalized to fiber CSA and fiber volume, respectively. V(o)/fiber length was dependent on fiber MHC content but independent of training status. CONCLUSION: Fiber hypertrophy was sufficient to account for intergroup differences in P(o) and peak power of slow and fast fibers. There was no evidence that the intrinsic contractility of slow or fast fibers, as evaluated by force, shortening velocity, and power normalized to the appropriate fiber dimensions, differed between RT and NT groups.     

Effect of recovery mode following hind-limb suspension on soleus muscle composition in the rat.

The purpose of this study was to compare the effects of two different recovery modes from hind-limb suspension-induced hypodynamia on whole body and muscle (soleus) growth as well as soleus composition and size changes of different fiber types within this same muscle. Following 28 days of tail-suspension, rats were returned to their cages and sedentarily recovered (HS), or were exercised by running on a treadmill 5 days/wk, at progressively increasing workloads (HR) for one month. Sedentary and running control groups of animals (CS, CR) were also evaluated for comparative purposes. The exercise program, which was identical for CR and HR groups, had no effect on body wt., soleus wt., soleus muscle composition or fiber size in CR rats. Atrophied soleus muscle and reduced soleus wt./body wt. ratio (both 60% of control) had returned to control values by day 7 of recovery in both suspended groups despite the fact that whole body wt. gain was significantly reduced (p less than 0.05) in HR as compared to HS rats. Atrophied soleus Type I fiber mean cross-sectional area in both HR and HS groups demonstrated similar and significant (p less than 0.01) increases during recovery. Increases in Type IIa and IIc fiber area during this same period were significant only in the HR group. While the percentage area of muscle composed of Type I fibers increased in both hypodynamic groups during recovery, the reduction in area percentage of muscle made up of Type IIa fibers was again only significant in the HR group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Myosin and actin content of human skeletal muscle fibers following 35 days bed rest

Biopsy samples were taken from the vastus lateralis muscle of seven male subjects pre- and post-35 days bed rest (BR). The myosin heavy chain (MHC) isoform distribution of the samples was determined by densitometry of MHC bands separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Individual muscle fibers were dissected from biopsy samples pre-BR ( n =143) and post-BR ( n =144). They were studied as regards cross-sectional area (CSA), myosin content by quantitative electrophoresis and myosin actin (M/A) ratio by densitometry of myosin and actin bands of individual muscle fibers. All fibers were typed according to their MHC isoform content determined by SDS-PAGE. A decrease in MHC-1 relative content and an increase in MHC-2X content of whole muscle samples were found, suggesting a slow to fast shift in muscle phenotype. Consistently, fiber type distribution was shifted toward type 2X and 2AX fibers. Muscle fiber atrophy occurred at variable extent among fiber types. Myosin concentration was significantly lower in type 1 and type 2A muscle fibers post-BR than pre-BR, whereas M/A ratio did not vary. The latter findings indicate a disproportionate loss of myosin compared with fiber CSA and a proportional loss of myosin and actin.